CN104854206A - Photocurable optical adhesive agent composition and cured product thereof, and liquid crystal display device - Google Patents

Abstract

Provided are a photocurable optical adhesive composition having excellent flexibility in a cured product and exhibiting a refractive index close to that of glass, a cured product thereof, and a liquid crystal display device having strong impact resistance and excellent brightness. Specifically, a photocurable optical adhesive composition composed of urethane (meth)acrylic acid having a flexible structure is used for the photocurable optical adhesive layer. An ester (A), a polymerizable diluent (B), a compound (C) represented by the following structural formula (1), and a photopolymerization initiator (D) are essential components. (In formula (1), R ¹ represents a straight-chain or branched aliphatic hydrocarbon group with 2 to 9 carbon atoms, R ² represents a hydrogen atom, an alkyl group with 1 to 3 carbon atoms, R ³ represents a hydrogen atom, C1-3 alkyl, n is an integer of 0-5.)

Description

Photocurable optical adhesive composition, cured product thereof, and liquid crystal display device

technical field

The present invention relates to bonding of optical lens members, bonding of a liquid crystal panel and a cover glass in a liquid crystal display device, bonding of a liquid crystal panel and a touch panel substrate, or bonding of a touch panel substrate and a cover glass A photocurable optical adhesive composition, and a liquid crystal display device using the adhesive composition.

Background technique

Liquid crystal display devices have a structure in which an LCD module composed of a liquid crystal cell, a polarizing plate, an optical film, and various protective films is laminated on a cover glass; touch panels have a structure in which the LCD module, a transparent electrode substrate, and a cover glass are laminated. formed structure. As a means of laminating these members, generally from the viewpoint of improving contrast and brightness, the above-mentioned members are generally pasted with an adhesive tape of a transparent resin called OCA, but it is difficult to stick to the adhesive tape. The shortcoming of fine unevenness (following the height difference) at the junction.

Therefore, in recent years, as an alternative to OCA, the market scale of liquid OCA (L-OCA) which is superior to OCA in following height differences is expanding. The L-OCA is used for bonding cover glass and ITO film, so its cured product is required to be flexible enough to absorb impact from the outside. For example, the following LOCA materials are known, which include: Monofunctional monomers in the group consisting of ester acrylate, phenoxyethyl acrylate and trimethylolpropane formalal acrylate; photopolymerization initiators; selected from dibutoxyethoxyethylhexyl Plasticizers and chain transfer agents in the group consisting of diacid esters and dibutoxyethoxyethyl formal (see, for example, Patent Document 1).

However, the LOCA material has a soft structure in its polymer structure and is compounded with a plasticizer so that it can exhibit fluidity and elongation of the cured product, but the refractive index of the cured product is different from that of the glass cover located on the outermost layer. The plate is relatively low, and as a result, the light transmittance decreases.

prior art literature

patent documents

Patent Document 1: Japanese National Publication No. 2011-511851

Contents of the invention

The problem to be solved by the invention

Therefore, the problem to be solved by the present invention is to provide a photocurable optical adhesive composition having excellent flexibility of the cured product and exhibiting a refractive index close to that of glass, a cured product thereof, and a liquid crystal display having strong impact resistance and excellent brightness. device.

solutions to problems

The inventors of the present invention conducted intensive studies to solve the above-mentioned problems, and found that a polyurethane resin having a flexible structure was used as the resin used in the photocurable optical adhesive composition, and a plasticizer with a specific chemical composition was used as the plasticizer. The present invention has been accomplished by achieving both softness and high refractive index of the cured product in the case of a material with a different structure.

That is, the present invention provides a photocurable optical adhesive composition characterized by comprising urethane acrylate (A) having a flexible structure, other radically polymerizable monomer (B), and the following structural formula The compound (C) shown in (1) and a photoinitiator (D) are essential components.

(R ¹ represents a straight chain or branched aliphatic hydrocarbon group with 2 to 9 carbon atoms, R ² represents a hydrogen atom, an alkyl group with 1 to 3 carbon atoms, R ³ represents a hydrogen atom, and an alkyl group with 1 to 3 carbon atoms The alkyl group, n is the integer of 0～5.).

The present invention also provides a cured product formed by curing the aforementioned photocurable optical adhesive composition.

The present invention also provides a liquid crystal display device, characterized in that the above-mentioned photocurable optical adhesive composition is coated or filled on the LCD module or the transparent electrode substrate of the liquid crystal display device, and then the cover glass or transparent The electrode substrate is then irradiated with light to cure the composition.

The effect of the invention

According to the present invention, it is possible to provide a photocurable optical adhesive composition having excellent flexibility of a cured product and exhibiting a refractive index close to that of glass, a cured product thereof, and a liquid crystal display device having strong impact resistance and excellent brightness.

Description of drawings

1 is a cross-sectional view of a liquid crystal display device having an out cell touch panel of the present invention.

2 is a cross-sectional view of a liquid crystal display device having a resistive touch panel of the present invention.

3 is a cross-sectional view of a liquid crystal display device having an In-cell/On-cell touch panel according to the present invention.

Detailed ways

The flexible urethane acrylate (A) used in the present invention is a urethane (meth)acrylate resin having a flexible structure in its resin structure, and examples of the flexible structure include An alkyl structure, a polyoxyalkylene structure, an aliphatic polyester structure, or an aliphatic polycarbonate structure.

Here, examples of the alkylene structure include ethylene, propylene, isoisopropyl, butylene, isobutylene, cyclohexane-1,4-diyl, cyclohexane-1, An aliphatic hydrocarbon group having 2 to 8 carbon atoms having a linear, branched or cyclic structure such as 4-dimethyl.

Next, examples of the polyoxyalkylene structure include polyoxyethylene, polyoxypropylene, polyoxy-1,2-propylene, and polyoxybutylene, where the number of carbon atoms in the alkylene portion is 2. The structure of ~4. In addition, a structure in which the number of repeating units of the polyoxyalkylene structure ranges from 20 to 200 is preferable from the viewpoint of excellent flexibility of the cured product of the adhesive agent finally obtained.

Next, the aliphatic polyester structure includes a polyester structure having a linear or branched alkylene group having 2 to 12 carbon atoms as an aliphatic hydrocarbon moiety.

Next, the aliphatic polycarbonate structure includes an aliphatic carbonate structure having a linear or branched alkylene group having 2 to 8 carbon atoms as an aliphatic hydrocarbon moiety.

Among these, an alkylene structure or a polyoxyalkylene structure is particularly preferable from the viewpoint of excellent flexibility and elongation when a cured product is formed.

The above-mentioned urethane acrylate (A) having a soft structure specifically includes the following: a diisocyanate compound (a), an aliphatic diol (b), a hydroxyl group-containing (meth)acrylate compound ( c) a substance having a structure obtained by reacting an essential raw material component; or, a diisocyanate compound ( a) A substance with a structure formed by reacting with it, etc.

The diisocyanate compound (a) used here includes, for example, 1,3-benzenediisocyanate, 1,4-benzenediisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2' -Aromatic diisocyanates such as diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate; isophorone diisocyanate, 2,2'-diisocyanate Aliphatic diisocyanates such as cyclohexylmethane diisocyanate, 2,4'-dicyclohexylmethane diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate. In the present invention, among these, aliphatic diisocyanate is particularly preferable from the viewpoint of transparency.

Next, the aliphatic diol (b) is a raw material for introducing a flexible structure into the aforementioned urethane acrylate (A), and examples thereof include alkylene glycol, polyalkylene glycol, aliphatic polycarbonate Ester diols, etc.

Here, examples of the alkylene glycol include ethylene glycol, 1,3-propanediol, 1,2-propanediol, tetramethylene glycol, 1,4-cyclohexanediol, 1,4- Cyclohexanedimethanol, etc.

Moreover, examples of polyalkylene glycol include polyethylene glycol, poly-1,3-propylene glycol, poly-1,2-propylene glycol, polytetramethylene glycol, and the like.

As the aliphatic polycarbonate diol, for example, one obtained by reacting an alkylene carbonate and an alkylene glycol can be used arbitrarily. The alkylene carbonate used here specifically includes ethylene carbonate, trimethylene carbonate, 1,2-propylene carbonate, 1,2-butylene carbonate, 1,3-carbonic acid Alkylene carbonates such as butylene and 1,2-pentylene carbonate.

Specific examples of the alkylene glycol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 1,7-heptanediol. Diol, 1,8-octanediol, 2-methyl-1,8-octanediol, neopentyl glycol, 2-ethyl-1,6-hexanediol, 2-methyl-1,3 -Propylene glycol, 3-methyl-1,5-pentanediol, 2,4-dimethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol and other branched chains diol.

Next, examples of the cyclic ester compound (b') include γ-butyrolactone, γ-valerolactone, δ-valerolactone, ε-caprolactone, ε-methylcaprolactone, ε - Ethylcaprolactone, ε-propylcaprolactone, 3-penten-4-lactide, 12-dodeclide, γ-laurolactone, and the like.

Among these, alkylene glycols or polyalkylene glycols are particularly preferable from the viewpoint of excellent flexibility and elongation in cured products. In addition, those in which the number of repeating units of the oxyalkylene structure of the polyalkylene glycol is in the range of 50 to 200 are preferable from the viewpoint of better flexibility of the cured product. Furthermore, among polyalkylene glycols, polyethylene glycol or polypropylene glycol is particularly preferable from the viewpoint of flexibility of a cured product.

Next, specific examples of the hydroxyl group-containing (meth)acrylate compound (c) include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxypropyl (meth)acrylate, Hydroxybutyl Ester, Neopentyl Glycol Mono(meth)acrylate, 4-Hydroxycyclohexyl (meth)acrylate, 1,6-Hexanediol Mono(meth)acrylate, Glyceryl Di(meth)acrylate Aliphatic (meth)acrylate compounds such as esters, trimethylolpropane di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate;

4-Hydroxyphenyl (meth)acrylate, β-hydroxyphenylethyl (meth)acrylate, 4-hydroxyphenylethyl (meth)acrylate, 1-phenyl-2-hydroxyethyl (meth)acrylate , 3-hydroxy-4-acetylphenyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl acrylate and other (meth)acrylate compounds with aromatic rings in the molecular structure, other Substances obtained by adding a cyclic ester compound to a compound containing an acryloyl group in the hydroxyl group, etc.

Here, examples of the cyclic ester compound include γ-butyrolactone, γ-valerolactone, ζ-valerolactone, ε-caprolactone, ε-methylcaprolactone, ε-ethyl Caprolactone, ε-propylcaprolactone, 3-penten-4-lactide, 12-dodeclide, γ-laurolactone, etc.

In addition, when using a compound obtained by adding a cyclic ester compound to a hydroxyl group-containing acryloyl group-containing compound, from the viewpoint of obtaining moderate flexibility, it is preferable to add 1 mole of the hydroxyl group-containing acryloyl group-containing compound. 2 to 4 moles of cyclic ester compounds.

Among these, 2-hydroxyethyl (meth)acrylate or its ε-caprolactone adduct is particularly preferable from the viewpoint of excellent flexibility of the cured product when used as an adhesive. In the case of , it is preferable that 2 or 3 moles of ε-caprolactone adducts are added to 1 mole of 2-hydroxyethyl (meth)acrylate.

The method of reacting the above-mentioned diisocyanate compound (a), alkylene glycol or polyalkylene glycol (b), and hydroxyl group-containing (meth)acrylate compound (c) includes the following methods, etc. : a diisocyanate compound (a) and an alkylene glycol or polyalkylene glycol (b) are mixed with a hydroxyl group contained in the aforementioned alkylene glycol or polyalkylene glycol (b) and a diisocyanate compound ( a) The molar ratio [(OH)/(NCO)] of the isocyanate group it has is used in the range of 1/0.5 to 1/2.0, and a known and commonly used carboxyl is used as needed in the temperature range of 20 to 120°C Esterification catalyst makes it react, obtains the intermediate containing isocyanate group as the reaction product, then, this intermediate and containing hydroxyl (meth)acrylic acid ester compound (c) in the aforementioned molecular structure and the aforementioned hydroxyl (methyl) ) The molar ratio [(OH)/(NCO)] of the hydroxyl group of the acrylate compound (c) to the isocyanate group of the above-mentioned intermediate is used in the range of 1/2 to 1/10, and the range is 20 to 120 °C temperature range, if necessary, using a known and commonly used urethanization catalyst.

In addition, examples of the method of producing the above-mentioned urethane (meth)acrylate (A) having an alkylene structure or a polyoxyalkylene structure include a method in which a diisocyanate compound (a), an alkylene A method in which diol or polyalkylene glycol (b) and a hydroxyl group-containing (meth)acrylate compound (c) are fed together and reacted; the diisocyanate compound (a) is combined with the aforementioned hydroxyl group-containing (meth)acrylate compound (meth) ) A method of reacting the acrylate compound (c) with the alkylene glycol or polyalkylene glycol (b).

The above-mentioned urethane (meth)acrylate (A) having an alkylene structure or a polyoxyalkylene structure obtained in this way can obtain a composition with a lower viscosity, containing 30 to 50% by mass of polymerizable diluent The viscosity at 25°C in the state of the agent is in the range of 10 to 500 Pa·s.

Next, examples of the polymerizable diluent (B) used in the photocurable resin composition of the present invention include phenylbenzyl (meth)acrylate (PBA), phenylthioethyl (meth)acrylate ( PTEA), o-phenylphenoxyethyl (meth)acrylate (OPPEA), naphthylthioethyl (meth)acrylate (NTEA) and other high refractive index monofunctional (meth)acrylate compounds; and (meth) base) n-butyl acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate , Isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, benzyl (meth)acrylate, glycidyl (meth)acrylate, morpholine (meth)acrylate, (meth)acrylate Base) 2-hydroxyethyl acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, diethylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate base) acrylate, dipropylene glycol mono(meth)acrylate, 2-methoxyethyl (meth)acrylate, methoxydiethylene glycol (meth)acrylate, methoxytriethylene glycol ( Meth)acrylate, methoxypolyethylene glycol (meth)acrylate, 2-butoxyethyl (meth)acrylate, butoxytriethylene glycol (meth)acrylate, (methyl ) 2-ethoxyethyl acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, ethoxypolyethylene glycol (meth)acrylate, 4-nonylphenoxy Ethylene glycol (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, caprolactone modified tetrahydrofurfuryl (meth)acrylate, (meth)cyclohexyl acrylate, (meth) ) isobornyl acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, cyclohexyl (meth)acrylate, cyclohexyl methyl (meth)acrylate, cyclohexylethyl (meth)acrylate ester, dicyclopentyl (meth)acrylate, dicyclopentyloxyethyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate Monofunctional (meth)acrylates such as esters, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate; acrylamide, dimethylacrylamide, diethylpropene Amide, hydroxyethylacrylamide, dimethylaminopropylacrylamide and other monofunctional acrylamide;

Ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate Meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, tetrabutylene glycol di(meth)acrylate, 1 ,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, neopentyl glycol di( Meth)acrylate, dicyclopentyl di(meth)acrylate, glycerol di(meth)acrylate, neopentyl glycol hydroxypivalate di(meth)acrylate, caprolactone modified hydroxy Neopentyl glycol di(meth)acrylate pivalate, Trimethylolpropane di(meth)acrylate modified with hydroxypivalaldehyde, 1,4-cyclohexanedimethanol di(meth)acrylate Other 2-functional aliphatic (meth)acrylate compounds;

Trimethylolpropane tri(meth)acrylate, trimethylolpropane ethylene oxide adduct tri(meth)acrylate, trimethylolpropane propylene oxide adduct tri( Meth)acrylate, pentaerythritol tri(meth)acrylate, glycerol tri(meth)acrylate, alkyl-modified dipentaerythritol tri(meth)acrylate, ditrimethylolpropane tetra(methyl) ) acrylate, tetra(meth)acrylate of the ethylene oxide adduct of ditrimethylolpropane, tetra(meth)acrylate of the propylene oxide adduct of ditrimethylolpropane, di Trifunctional or higher aliphatic (meth)acrylate compounds such as penta(meth)acrylate of pentaerythritol and hexa(meth)acrylate of dipentaerythritol, and the like.

Among these, monofunctional (meth)acryloyl group-containing compounds such as monofunctional (meth)acrylates and monofunctional acrylamides are particularly preferable from the viewpoint of flexibility of cured products. (Meth) Isobornyl acrylate is preferable from the viewpoint of being excellent in thermal yellowing resistance, and morpholine (meth)acrylate and dimethylacrylamide are preferable from the viewpoint of being excellent in heat-and-moisture resistance.

Here, the blending amount of the polymerizable diluent (B) is 10 to 80% by mass relative to the total mass of the urethane (meth)acrylate resin (A). From the effect of increasing the refractive index and reducing the viscosity, Prominently starting from this point is preferred. Furthermore, it is especially preferable that it is 20-60 mass %.

Next, the compound (C) used in the present invention is represented by the following structural formula (1), and functions as a plasticizer in the adhesive composition of the present invention.

(R ¹ represents a straight chain or branched aliphatic hydrocarbon group with 2 to 9 carbon atoms, R ² represents a hydrogen atom, an alkyl group with 1 to 3 carbon atoms, R ³ represents a hydrogen atom, and an alkyl group with 1 to 3 carbon atoms alkyl, n is an integer of 0 to 5.)

In the present invention, since the plasticizer having the above chemical structure is used, the cured product has excellent flexibility and can exhibit a refractive index close to that of glass.

Here, as described above, R ¹ is a straight-chain or branched aliphatic hydrocarbon group having 2 to 9 carbon atoms, specifically, ethylene, n-propylene, isopropylene, butylene, etc. Base etc. In addition, n is a repeating unit and is an integer of 0 to 5, and is particularly preferably 0 or 1 from the viewpoint of excellent balance between flexibility and refractive index.

In addition, R ² is specifically a hydrogen atom, a methyl group, or a n-propyl group, and is particularly preferably a hydrogen atom from the viewpoint of the refractive index. R ³ is specifically a hydrogen atom, a methyl group, or a n-propyl group, and is particularly preferably a hydrogen atom from the viewpoint of the refractive index.

The compound (C) specifically includes propylene glycol dibenzoate, diethylene glycol dibenzoate, dipropylene glycol dibenzoate, ethylene glycol dibenzoate, 1,3- Propylene glycol dibenzoate, 1,5-pentanediol dibenzoate, 1,6-hexanediol dibenzoate, 1,9-nonanediol dibenzoate, neopentyl glycol Dibenzoate, Butylethylpropylene Glycol Dibenzoate, Trimethylolpropane Dibenzoate, etc. Among these, propylene glycol dibenzoate, diethylene glycol dibenzoate, dipropylene glycol dibenzoate, and ethylene glycol dibenzoate are particularly preferable from the viewpoint of the refractive index.

As a compounding ratio of the said compound (C), it is preferable that it becomes the ratio of 1-50 mass % in a composition.

The photopolymerization initiator (D) used in the present invention includes, for example, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1-[4-( 2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2,2'-dimethoxy-1,2-diphenylethane-1- Ketone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2-methyl-1-[4- (Methylthio)phenyl]-2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, Benzophenone, 4-methylbenzophenone, 4-phenylbenzophenone, 4-(4-methylphenylthio)benzophenone, thioxanthone, 2-isopropylthioxanthene Ketone, 4-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, 2,4-di Chlorothixanthone, etc.

In order to express sufficient curability, these photopolymerization initiators (D) are preferably compounded in the range of 0.1 to 25 parts by mass with respect to a total of 100 parts by mass of photopolymerizable substances having (meth)acryloyl groups in the composition. In particular, it is more preferably in the range of 1 to 5 parts by mass.

In addition, in the present invention, those having an aromatic nucleus as a substituent such as 4-phenylbenzophenone and 4-(4-methylphenylthio)benzophenone are used as the photopolymerization initiator (D). In the case of a benzophenone-based photopolymerization initiator, it is preferable to use 2,4,6-trimethylbenzoyldiphenylphosphine oxide or the like in the long wavelength range of 380 nm to 600 nm from the viewpoint of excellent transparency. Photosensitive photopolymerization initiators; 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-1,2-diphenylethan-1-one, etc. Substances that are photosensitive in the wavelength region.

In addition, in the present invention, those having an aromatic nucleus as a substituent such as 4-phenylbenzophenone and 4-(4-methylphenylthio)benzophenone are used as the photopolymerization initiator (D). In the case of benzophenone-based photopolymerization initiators, it is preferable to use 2,4,6-trimethylbenzoyldiphenylphosphine oxide in combination with them from the viewpoint of good curability. Photopolymerization initiators with photosensitivity in the long wavelength range below 600nm, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-1,2-diphenylethan-1-one, etc. A substance having photosensitivity in a short-wavelength range of 200 nm to 380 nm is preferable from the viewpoint of excellent curability. In particular, from the viewpoint of better curability, it is preferable to use the aforementioned photopolymerization initiator having photosensitivity in the long wavelength region and the photopolymerization initiator having photosensitivity in the short wavelength region in combination.

The photocurable optical adhesive composition of this invention can add various photosensitizers together with the said photoinitiator (D). Examples of the photosensitizer include amines, ureas, sulfur-containing compounds, phosphorus-containing compounds, chlorine-containing compounds, nitriles, or other nitrogen-containing compounds, and these may be used alone or in combination of two or more. It is preferable that the addition amount at the time of adding these photosensitizers is the range of 0.01-25 mass parts with respect to 100 mass parts of urethane (meth)acrylate resins (A).

The photocurable optical adhesive composition described in detail above can be suitably used as an adhesive used for bonding optical lens members, or a so-called LOCA for bonding various substrates in a liquid crystal display device. In the present invention, it is particularly preferably used as LOCA from the viewpoint of being excellent in flexibility after curing and exhibiting a refractive index close to that of glass. Here, the liquid crystal display device is composed of a liquid crystal panel, a touch panel substrate if necessary, and a cover glass. The liquid crystal panel is composed of a liquid crystal cell, a polarizing plate, and various optical films. The photocurable optical film of the present invention The adhesive composition can be used as an adhesive between these various substrates. Specifically, it can be suitably used for bonding of an LCD module and a cover glass in a liquid crystal display device, bonding of a liquid crystal panel and a touch panel substrate, bonding of a touch panel substrate and a cover glass, or the like.

In addition, when used in a liquid crystal display device with a touch panel structure, the liquid crystal display device can be any of the external unit type, cover glass integrated type, In-cell type, and On-cell type. For the built-in unit type, it can be used for the bonding of the liquid crystal panel and the touch panel substrate, and the bonding of the touch panel substrate and the cover glass. In addition, for the cover glass integrated type, it can be used for bonding the cover glass Bonding of the substrate on which the electrodes of the capacitive touch sensor are formed and the liquid crystal panel. For In-cell type and On-cell type, it can be used for bonding liquid crystal panel and cover glass.

In addition, when used for bonding a liquid crystal panel and a cover glass, decorative printing can be applied to the back surface of the cover glass. At this time, there is usually a case where a level difference occurs between the cover glass and the decorative printing part, but the photocurable optical adhesive composition of the present invention is liquid before curing, so it exhibits excellent follow-up to such a level difference. sex.

The photocurable resin composition of this invention can be hardened by irradiating ultraviolet-ray/visible light.

When curing with ultraviolet rays, it can be cured by irradiation with mercury lamps such as ultra-high pressure mercury lamps, high-pressure mercury lamps, and low-pressure mercury lamps, xenon lamps, carbon arcs, and metal halide lamps. The exposure amount of ultraviolet rays at this time is preferably in the range of 0.1 to 3000 mJ/cm ² .

The method for manufacturing the liquid crystal display device of the present invention from the photocurable optical adhesive composition described in detail above includes: coating or filling on a liquid crystal panel or a touch panel, and then bonding a cover glass or a touch panel. A method in which the control panel substrate is then irradiated with light to cure it.

Example

Next, although an Example and a comparative example are given and this invention is demonstrated concretely, this invention is not limited to these. In addition, the parts and % in an example are mass basis except light transmittance.

Examples 1-7 and Comparative Examples 1-3

Each component was mixed according to the composition ratio described in Table 1, and the photocurable resin composition was prepared. It should be noted that the composition ratios in Table 1 are mass standards.

Evaluation of the refractive index, color tone, and cured product elongation was performed using this according to the following evaluation methods.

[refractive index]

The test piece obtained by curing the photocurable resin composition obtained in each example and comparative example into a sheet shape was measured with an Abbe refractometer ("NAR-3T" manufactured by ATAGO CO., LTD, 25°C). .

[tone]

The photocurable resin composition produced in each Example and Comparative Example was sandwiched between glass plates, and the cured sample with a thickness of 200 micrometers was produced. The b* value of the prepared sample was measured with a color difference meter. The results are shown in Table 1.

[Cured product elongation]

The photocurable resin composition produced in each Example and Comparative Example was cured into a sheet shape with a thickness of 0.2 mm. The elongation when the cured product was subjected to a tensile elongation test to break was measured. The results are shown in Table 1.

[Table 1]

Table 1

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Comparative example 1 Comparative example 2 Comparative example 3 Urethane Acrylate A 45 45 45 45 45 45 45 Urethane Acrylate B 45 Urethane Acrylate C 45 Urethane acrylate D 45 Monofunctional acrylate monomer A 10 10 10 10 10 10 10 10 Monofunctional acrylate monomer B 5 5 5 5 5 5 5 5 Monofunctional acrylate monomer C 2 2 2 2 2 2 2 2 Monofunctional acrylate monomer D 17 17 Plasticizer A 20 20 20 20 Plasticizer B 20 Plasticizer C 20 Plasticizer D 20 Plasticizer E 20 Plasticizer F 20 20 chain transfer agent 5 Photopolymerization Initiator A 4 4 4 4 4 4 4 4 4 4 Photopolymerization Initiator B 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Refractive index of cured product 1.51 1.54 1.5 1.53 1.50 1.50 1.50 1.47 1.5 1.5 Color of cured product (b*) 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.5 0.5 Cured product elongation (%) 350 340 320 320 350 300 300 340 350 360

Here, each compounding component in Table 1 is as follows.

Urethane acrylate A: Polyether-based urethane acrylate (PPG 10000/IPDI/HEA)

Urethane acrylate B: Polyether-based urethane acrylate (PPG 10000/IPDI/HPA)

Urethane acrylate C: Polyether-based urethane acrylate (PPG10000/H ₁₂ MDI/HEA)

Urethane acrylate D: Polyether-based urethane acrylate (PPG10000/H ₁₂ MDI/HPA)

Monofunctional acrylate monomer A: isobornyl acrylate,

Monofunctional acrylate monomer B: Dimethacrylamide,

Monofunctional acrylate monomer C: acryloylmorpholine,

Monofunctional acrylate monomer D: phenoxyethyl acrylate,

Plasticizer A: Propylene glycol dibenzoate,

Plasticizer B: diethylene glycol dibenzoate,

Plasticizer C: dipropylene glycol dibenzoate,

Plasticizer D: dipropylene glycol dibenzoate,

Plasticizer E: Dibutoxyethoxyethyl formal,

Plasticizer F: Dibutoxyethoxyethyl adipate,

Chain transfer agent: 3-mercaptopropionate,

Photopolymerization initiator A: 1-hydroxyhexyl-phenyl-ketone,

Photopolymerization initiator B: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide

Next, an example of the structure of a liquid crystal display device when using the photocurable optical adhesive composition of this invention as LOCA is shown.

1 is an example of a liquid crystal display device with an external unit type touch panel, between the liquid crystal panel 5 and the touch panel substrate 4, and between the touch panel substrate 4 and the glass substrate 1 on which the decorative printing 2 is applied. An example in which the photocurable optical adhesive composition of the present invention was used.

FIG. 2 is an example of a liquid crystal display device having a resistive film type touch panel. The photocurable optical film of the present invention is used between a film or glass substrate 8 provided with ITO 7 and a glass substrate 1 on which decorative printing 2 is applied. Examples of Adhesive Compositions.

FIG. 3 is an example of a liquid crystal display device having an In-cell/On-cell touch panel. The photocurable optical adhesive of the present invention is used between the liquid crystal panel 5 and the glass substrate 1 on which the decorative printing 2 is applied. Examples of adhesive compositions.

Explanation of reference signs

1…Glass substrate

2…decorative printing

3...Photocurable optical adhesive layer

4...Touch panel substrate

5…LCD panel

6…height difference

7…ITO

8…film or glass substrate

Claims (7)

1. a light solidified optical cement composition, it is characterized in that, there is the compound (C) shown in carbamate (methyl) acrylate (A) of flexible structure, polymerizability thinner (B), following structural formula (1) and Photoepolymerizationinitiater initiater (D) as essential component

R ¹represent the aliphatic alkyl of the straight or branched of carbonatoms 2 ~ 9, R ²represent the alkyl of hydrogen atom, carbonatoms 1 ~ 3, R ³represent the alkyl of hydrogen atom, carbonatoms 1 ~ 3, n is the integer of 0 ~ 5.

2. light solidified optical cement composition according to claim 1, wherein, carbamate (methyl) acrylate (A) described in flexible structure has alkylen structures, poly (oxyalkylene) based structures, aliphatic poly ester structure or aliphatic polycarbonate structure as flexible structure.

3. light solidified optical cement composition according to claim 1, wherein, the compounding ratio of described compound (C) is the ratio reaching 1 ~ 50 quality % in the composition.

4. light solidified optical cement composition according to claim 3, wherein, the compounding amount of described polymerizability thinner (B) is 10 ~ 80 quality % relative to the synthesis quality of itself and described carbamate (methyl) acrylate resin (A).

5. light solidified optical cement composition according to claim 1, wherein, described polymerizability thinner (B) is for simple function type is containing the compound of (methyl) acryl.

6. a cured article, makes the light solidified optical cement composition according to any one of Claims 1 to 5 be solidified to form.

7. a liquid crystal indicator, it is characterized in that, by in the light solidified optical cement composition coating according to any one of Claims 1 to 5 or the liquid crystal panel being filled in liquid crystal indicator or contact panel substrate, and then fit cover-plate glass or contact panel substrate, then carry out rayed and said composition is solidified to form.